Drawing method, drawing apparatus and display apparatus

ABSTRACT

A method is provided to reliably form shot drops on all of a plurality of pixel areas. The method comprises a step of forming a plurality of shot drops by ejecting droplets from a plurality of nozzles of a drawing apparatus to a plurality of pixel areas on a substrate. The step of forming the plurality of shot drops includes a step of forming additional shot drops near predetermined ones of the plurality of shot drops.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/959,919filed Oct. 6, 2004, which claims priority to Japanese Patent ApplicationNo. 2003-348423 filed Oct. 7, 2003 which is hereby expresslyincorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a drawing method and a drawingapparatus operating in an ink-jet mode for ejecting droplets of a liquidmaterial, and to a display apparatus.

2. Background Art

As a conventional method of forming a filter material and the like for acolor filter in the pixel areas on a substrate on which droplets areejected by using a drawing apparatus in an ink-jet mode, there is amethod in which droplets (a material for a color filter) aresequentially arranged in an array in pixel areas of each colorconstituting the color filter.

In the conventional method, however, there is a problem in that theperiphery of the pixel areas, a corner part thereof in particular, isnot sufficiently filled with the droplets. Moreover, the droplets aresequentially ejected on the pixel areas and on a boundary layerseparating each of the pixel areas, so that the patterns of dropletsarrangement are different in each of the pixel areas. In other words,the color tone is not uniform in each of the pixel areas.

The present invention has been achieved in view of the aforementionedproblems. An object of the invention is to provide a drawing method anda drawing apparatus which are capable of filling the corner part of thepixel areas with droplets and arranging the droplets uniformly in colortone in each of the pixel areas, and to provide a display apparatus.

SUMMARY

A drawing method according to the invention comprises a step of forminga plurality of shot drops by ejecting droplets from a plurality ofnozzles of a drawing apparatus to a plurality of pixel areas on asubstrate, wherein the step of forming the plurality of shot dropsincludes a step of forming an additional plurality of shot drops aroundpredetermined shot drops.

According to this drawing method, the shot drops reliably spread on allof the pixel areas by forming additional shot drops on the parts of thepixel areas on which the shot drops do not easily spread. Thereby, eachof the pixel areas is filled with uniform shot drops.

In this case, it is preferable that the step of forming the plurality ofshot drops includes a step of forming the predetermined shot drops inthe vicinity of a corner part of the pixel areas.

With this constitution, the arrangement of additional shot drops can beclarified by predetermining the shot drops which are hard to spread asthe shot drops at the corner part of the pixel areas.

In this case, it is preferable that the plurality of pixel areas arearranged parallel to an array of the plurality of nozzles and that thestep of forming the plurality of shot drops includes a step of formingthe shot drops by ejecting the droplets from the plurality of nozzles tothe plurality of pixel areas at about the same time (i.e., substantiallysimultaneously).

With these constitutions, the nozzles and each of the pixel areas existsequentially in the same positional relationship, and the shot drops canbe formed on a plurality of pixel areas at about the same time.

A drawing apparatus according to the invention comprises a plurality ofnozzles forming a plurality of shot drops by ejecting droplets to aplurality of pixel areas separated by a boundary layer on a substrate,wherein an additional plurality of shot drops are formed aroundpredetermined shot drops.

According to this drawing apparatus, additional shot drops can be formedat the periphery of the predetermined shot drops, and the shot drops canbe flexibly arranged on pixel areas with various shapes.

In this case, it is preferable that the plurality of nozzles arearranged parallel to the plurality of pixel areas and that the shotdrops are formed in the plurality of pixel areas at about the same time.

With this constitution, the nozzles and the pixel areas extend inparallel, so that the shot drops can be formed by ejecting droplets fromthe plurality of nozzles to the plurality of pixel areas at about thesame time, which enables an efficient arrangement of shot drops.

A display apparatus according to the invention is provided with a filtermaterial or a luminescence material in the pixel areas by theaforementioned drawing method or drawing apparatus.

Since the shot drops with the filter or luminescence material are formedon the pixel areas by using the aforementioned drawing method or drawingapparatus, the filter or luminescence material can be efficientlyprovided in the pixel areas of the display apparatus. Further, a displayapparatus capable of preventing the scattering of shot drops in thearrangement in each pixel area and capable of providing a favorabledisplay can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a frame format of Embodiment 1 in whichdroplets are arranged on pixel areas.

FIG. 2 is a view showing a frame format of Embodiment 2 in whichdroplets are arranged on pixel areas.

FIG. 3 is a perspective view showing an appearance of a drawingapparatus.

FIG. 4 is a plan view showing an arrangement of ejecting heads andnozzles in Embodiment 1.

FIG. 5( a) is a detail view showing a constitution of the ejecting headand FIG. 5( b) is a sectional view showing a constitution of thenozzles.

FIG. 6 is a block diagram illustrating a controller of the drawingapparatus.

FIG. 7( a) is a sectional view showing a constitution of a color filterdisplay apparatus and FIG. 7( b) is a view showing a frame format of amanufacturing apparatus of the color filter display apparatus.

FIG. 8( a) is a plan view showing a constitution of pixel areas of acolor filter and FIG. 8( b) is a sectional view of the color filter.

FIG. 9( a) is a sectional view showing a constitution of anelectroluminescence display apparatus and FIG. 9( b) is a view showing aframe format of a manufacturing apparatus of the electroluminescencedisplay apparatus.

FIG. 10( a) is a sectional view showing a constitution of a plasmadisplay apparatus and FIG. 10( b) is a view showing a frame format of amanufacturing apparatus of the plasma display apparatus.

DETAILED DESCRIPTION

A drawing method according to the invention will be described withreference to drawings. In this method, red (R), green (G) and blue (B)filter materials are ejected as droplets from nozzles of a drawingapparatus to be described later to pixel areas of a color filter, etc.Here, a description will be given by exemplifying the pixel areas of acolor filter. As shown in FIG. 8( b), a color filter 110 comprises atransparent filter substrate 111, a boundary layer 112 formed in alattice-like pattern on one surface of the filter substrate 111, pixelareas 105R, 105G, 105B which are separated by the boundary layer 112 andon which a filter material is coated, and an overcoat layer 114 whichcoats the boundary layer 112 and the filter material.

The pixel areas 105, as shown in FIG. 8( a) as an example, are separatedby the boundary layer 112 which is rectangular in a planar shape. Thelong side direction of each of the pixel areas 105 runs in parallel tothe y-axis direction. A plurality of red (R) pixel areas 105R extend inthe y-axis direction in an array, and a plurality of green (G) pixelareas 105G extend in the y-axis direction in an array, adjacent to thearray of red (R) pixel areas 105R. Similarly, a plurality of blue (B)pixel areas 105B extend in an array, adjacent to the array of green (G)pixel areas 105G. This arrangement is repeated in order of red (R), blue(B), green (G), to form an array of pixel areas 105.

Embodiment 1

A method of ejecting and coating a filter material as droplets from thenozzles of a drawing apparatus to the pixel areas 105 of the colorfilter 110 by using a drawing method according to the invention will nowbe described. In the color filter 110, as shown in FIG. 1, an array ofpixel areas 105R on which the red (R) filter material is coated isarranged on the filter substrate 111. In the drawing apparatus, nozzles77 are arranged to form two nozzle arrays 78 and 79 which run parallelto the y-axis direction of an ejecting head 68. The nozzles 77 in thenozzle array 78 and the nozzles 77 in the nozzle array 79 are shiftedfrom each other in the y-axis direction, and a nozzle pitch in they-axis direction of the ejecting head 68 is P. A plurality of ejectingheads 68 is arranged in the y-axis direction so that the nozzles 77extend sequentially in the y-axis direction at a pitch P.

With this constitution, either the pixel areas 105R or the ejecting head68 shifts relatively so that the pixel areas 105R can be locateddirectly below the ejecting head 68, to eject droplets 40 of the redfilter material from the nozzles 77 of the nozzle arrays 78 and 79 tothe pixel areas 105R. After the droplets have been shot to one of thepixel areas 105R, the droplets change into shot drops 1 in accordancewith the volume of the droplets 40. For example, one of the droplets 40ejected from a nozzle n2 of the nozzle array 78 changes into a shot dropc2 after being shot to one of the pixel areas 105R. Similarly, one ofthe droplets 40 ejected from a nozzle n3 of the nozzle array 79 changesinto a shot drop c3 after being shot to one of the pixel areas 105R. Inthis manner, the pixel areas 105R are coated with the red filtermaterial by a plurality of shot drops 1.

The outer peripheral diameter of the shot drops 1 is determined by thevolume and surface tension of the droplets 40 ejected from the nozzles77 and by the surface contact angle of the droplets 40 and the filtersubstrate 111. Therefore, the outer peripheral diameter of the shotdrops 1 can be varied by changing the volume of the droplets 40, andsuitable shot drops 1 can be arranged on pixel areas 105 with varioussizes. The volume of the droplets 40 can be varied in a range from, forexample, 0 pl (pico liter) to 42 pl. When the filter substrate 111 ismade of glass, the surface contact angle of the filter material and theglass is preferably 15 degrees. When the volume of the droplets 40 is 6pl, the outer peripheral diameter of the shot drops 1 is determined tobe 60 μm. When the volume of the droplets 40 is 26 pl, the outerperipheral diameter of the shot drops 1 is determined to be 100 μm.

Here, an example of coating the filter material will be brieflydescribed. First, there is a way of arranging seven shot drops 1 in theorder of c1, c2, c3, . . . , c7, for example, at about the centralposition of the short side direction of the pixel areas 105R in an arrayalong the long side direction. Each of the shot drops 1 mixes with eachother, spreads more widely compared with the case of spreading withoutmixing, and fills the pixel areas 105R. However, four corner parts ofthe rectangular pixel areas 105R are not easily and sufficiently filledwith the filter material only by the shot drops c1 and c7 that arelocated near the corner part. If the pixel areas 105R are not filledwith the filter material, there remains a part on which the red filtermaterial is not coated, which becomes an unclear area partly without reddisplay. In addition, a well-balanced color tone cannot be achievedbetween the red area and other pixel areas 105R. The same is true forthe green (G) and blue (B) pixel areas 105G and 105B.

In this embodiment, a plurality of shot drops 1 are arranged at thecorner parts of the pixel areas 105R which are not easily filled withthe filter material. Further in this embodiment, the size of the pixelareas 105R is determined by the arrangement of the nozzles 77 at a pitchP. More specifically, the size of the pixel areas 105R is determined bythe volume of the droplets 40, that is, the outer peripheral diameter ofthe shot drops 1 created by the droplets 40 and the number of the shotdrops 1. Thereby the droplets 40 can be efficiently arranged on thepixel areas 105R by ejecting from the nozzles 77.

Here, the nozzle pitch P of the ejecting head 68 in the y-axis directionis set at 60 μm, the space between the nozzle arrays 78 and 79 is set at80 μm and the volume of the droplets 40 ejected from the ejecting head68 is set at 6 pl. Since the filter substrate 111 is made of glass, theouter peripheral diameter Φ of the shot drops created by the droplets 40with the volume of 6 pl is set to be 60 μm. When seven drops, forexample, of the droplets 40 are arranged to contact with each other inthe long side direction (y-axis direction) of the pixel areas 105R, thelong side length of the pixel areas 105R is set to be 420 μm. When threedrops overlap each other by 20 μm in the short side direction (x-axisdirection), the short side length of the pixel areas 105R is set to be140 μm. The width of the boundary layer 112 is the same as the outerperipheral diameter of the shot drops, 60 μm. A plurality of pixel areas105R having this size is arranged in the y-axis direction with theboundary layer 112 as a boundary. The green (G) and blue (B) pixel areas105G and 105B are arranged in the same manner.

The drawing method in which the filter material is coated on these pixelareas 105 will be described. Either the pixel areas 105R or the ejectinghead 68 shifts relatively so that the pixel areas 105R to be coated withthe red (R) filter material can be located directly below the ejectinghead 68, to eject droplets 40 from nozzles n1 and n7, and to form shotdrops c10 and c12 respectively at the upper left and right corners ofone of the pixel areas 105R in FIG. 1. Next, the ejecting head 68 shiftsin the forward direction of x-axis by 40 μm to eject the droplets 40from nozzles n1, n3, n5 and n7 and shot drops c1, c3, c5 and c7 areformed. The center of the shot drop c1 (or x-coordinate) is locatedapart from the center of the shot drop c10 (x-coordinate) in the x-axisdirection by 40 and the shot drops c1 and c10 overlap each other by 20μm. The center of the shot drop c7 (or x-coordinate) is located apartfrom the center of a shot drop c12 (x-coordinate) in the x-axisdirection by 40 μm, and the shot drops c7 and c12 overlap each other by20 μm. The shot drops c3 and c5 are arranged apart from each other onthe y-axis line connecting the shot drops c1 and c7.

The ejecting head 68 shifts further in the forward direction of x-axisby 40 μm to eject the droplets 40 from the nozzles n1 and n7 and shotdrops c11 and c13 are formed. The shot drops c11 and c13 overlap theshot drops c1 and c7 by 20 μm, respectively. Then the ejecting head 68shifts further by 40 μm to eject the droplets 40 from nozzles n2, n4 andn6 and shot drops c2, c4 and c6 are formed. The shot drop c2 is arrangedbetween the shot drops c1 and c3 which have already been shot, the shotdrop c4 is arranged between the shot drops c3 and c5 and the shot dropc6 is arranged between the shot drops c5 and c7. Note that the shotdrops c1, c3, c5 and c7 are approximately arranged on the line parallelto the long side of the pixel areas 105R and which divides the shortside of the pixel areas 105R in half.

Coated on the pixel areas 105R are seven shot drops c1 to c7 arranged inan array on the central part thereof, shot drops c10 and c11 arranged onboth sides of the shot drop c1 in the x-axis direction and shot dropsc12 and c13 arranged on both sides of the shot drop c7 in the x-axisdirection. By arranging plural drops of shot drops 1 at the corner partsof the pixel areas 105R, the red (R) filter material can be reliablycoated on the entire pixel area of each pixel area 105R.

Also on other red (R) pixel areas 105R, the filter material is coated atthe same time in the same arrangement of the shot drop 1. On the pixelareas 105R adjacent to one of the pixel areas 105R on which the filtermaterial is coated by the nozzles n1 to n7, the filter material iscoated in the same manner and at the same time by seven nozzles 77starting from n9. For example, the nozzle n9 forms shot drops c14, c9and c15 in synchronization with forming the shot drops c10, c1 and c11by the nozzle n1. Note that the nozzles 77 located on the boundary layer112 between the pixel areas 105R are closed for stopping ejecting. Thiskind of nozzle 77 corresponds to the nozzle n8 between the nozzles n7and n9, and the like. In this manner, the filter material issimultaneously coated on the red (R) pixel areas 105R in the y-axisdirection. Since the shot drops 1 are coated on each of the pixel areas105R in the same arrangement, pixel areas 105R with uniform color tonecan be obtained.

The size of the pixel areas 105R can be easily changed by changing thenumber and size of the shot drops 1 to be shot on the pixel areas 105R.Although the explanation has been given by referring an example of thered (R) pixel areas 105R, the same goes for the green (G) and blue (B)pixel areas 105G and 105B.

Embodiment 2

Next, the case will be described where the same ejecting head 68 is usedand the droplets 40 are arranged more minutely with pitch P narrowed. Inthis case, as shown in FIG. 2, two ejecting heads 68 a and 68 b havingnozzles 77 at pitch P are arranged in parallel and shifted from eachother by an amount Q which is half of the pitch P. Each of the twoejecting heads 68 a and 68 b corresponds to one ejecting head 68 inEmbodiment 1.

Here, assuming that the nozzle pitch P of the ejecting heads 68 a and 68b in the y-axis direction is 60 μm and that both ejecting heads 68 a and68 b constitute one ejecting head group, the nozzle pitch Q is set to be30 μm. The space between each head array, that is, between nozzle arrays78 a and 79 a of the ejecting head 68 a, between nozzle arrays 78 b and79 b of the ejecting head 68 b and between nozzle arrays 78 a and 79 bis 80 μm. The volume of the droplets 40 ejected from the ejecting headgroup is set at 4 pl. The outer peripheral diameter Φ of the shot dropscreated by the droplets 40 with the volume of 4 pl is 40 μm. In thiscase, the length of the pixel areas 105 in the long side direction(y-axis direction) is 250 μm, which corresponds to the length of thearrangement in which eight drops of the droplets 40 overlap each otherby 10 μm. The length of the pixel areas 105 in the short side direction(x-axis direction) is 90 μm, which corresponds to the length of thearrangement in which three drops of the droplets 40 overlap each otherby 15 μm. The width of the boundary layer 112 corresponds to the minimumspace of the outer periphery between the shot drops 1 which do notoverlap each other, 20 μm.

In the drawing method in which the filter material is coated on thesepixel areas 105, either the pixel areas 105 or the ejecting head 68shifts relatively so that the pixel areas 105 to be coated with thefilter material can be located directly below the ejecting head 68 a, toeject droplets 40 from the nozzle n1, and to form a shot drop c30 at theupper left corner of one of the pixel areas 105 in FIG. 2. Next, theejecting head group shifts in the forward direction of x-axis by 25 μmto eject the droplets 40 from the nozzles n1 and n3 of the ejecting head68 a and shot drops c20 and c24 are formed. The center of the shot dropc20 (or x-coordinate) is located apart from the center of the shot dropc30 (x-coordinate) in the x-axis direction by 25 μm, and the shot dropsc20 and c30 overlap each other by 20 μm. The ejecting head 68 a shiftsin the forward direction of x-axis by 25 μm to eject the droplets 40from the nozzle n1 and a shot drop c31 is formed. The shot drops c31 andc20 overlap each other by 15 μm. From this state, the ejecting head 68 ashifts further by 55 μm to eject the droplets 40 from the nozzle n2 andn4 and shot drops c22 and c26 are formed. Subsequently, the ejectinghead group shifts by 80 μm and shot drops c21 and c25 are formed bynozzles m1 and m3 of the ejecting head 68 b. The ejecting head 68 bshifts by 55 μm and a shot drop c32 is formed by a nozzle m4 at theupper right corner of one of the pixel areas 105, and shifts by 25 μmand shot drops c23 and c27 are formed by nozzles m2 and m4. Finally, theejecting head 68 b shifts by 25 μm and a shot drops c33 is formed by thenozzle m4. The shot drop c27 overlaps the shot drop c32 and c33 by 15μm, respectively. Also, the shot drops c21 to c26 are arranged in thisorder each overlapping by 10 μm on the y-axis line connecting the shotdrops c20 and c27. Note that the shot drops c20, c21, c22, c23, c24,c25, c26 and c27 are approximately arranged on the line parallel to thelong side of the pixel areas 105R and which divides the short side ofthe pixel areas 105R in half.

Also on the adjacent pixel areas 105 in the y-axis direction with theboundary layer 112 as a boundary, the shot drops 1 can be arranged inthe same pattern by controlling each of the nozzles 77. Note that sincethe nozzle n5 next to the nozzle m4 by which the shot drops 1 arearranged at the corner part is located on the boundary layer 112, thenozzle n5 is closed for stopping ejecting the droplets 40. One of thepixel areas 105 next to the aforementioned pixel area is formed by eightnozzles 77 starting from m5, next to the nozzle n5. The space of theouter periphery between the shot drops c32 and c34 formed respectivelyby the nozzles m4 and m5 is 20 μm, which corresponds to the width of theboundary layer 112.

As described above, the nozzle pitch can be narrowed by using thecombination of ejecting heads 68, which enables more minute constitutionof the shot drops 1. Also in this case, since the shot drops 1 arecoated on each of the pixel areas 105R in the same arrangement, pixelareas 105R with uniform color tone can be obtained.

Next, a drawing apparatus used for the drawing method heretoforedescribed will be described. As shown in FIG. 3, a drawing apparatus 50comprises a head mechanism part 52 having a head part 60 for ejectingthe droplets 40, a work mechanism part 53 having a workpiece (work) 70to which the droplets 40 ejected from the head part 60 are ejected, aliquid material supply part 54 for supplying a liquid material 93 to thehead part 60, and a controller 55 for controlling these mechanisms and asupply part as a group.

The drawing apparatus 50 is equipped with a plurality of supporting legs56 placed on a floor and a surface table 57 placed on the upper side ofthe supporting legs 56. On the upper side of the surface table 57, thework mechanism part 53 is arranged to extend in a longitudinal direction(x-axis direction) of the surface table 57. On the upper side of thework mechanism part 53, the head mechanism part 52 supported at both theends by two pillars secured to the surface table 57 is arranged toextend in a direction perpendicular to the work mechanism part 53(y-axis direction). On one end of the surface table 57, the liquidmaterial supply part 54 for supplying the liquid material 93 is arrangedcommunicating with the head part 60 of the head mechanism part 52. Onthe underside of the surface table 57, the controller 55 is housed.

The head mechanism part 52 comprises: the head part 60 for ejecting theliquid material 93; a carriage 61 with the head part 60 thereon; ay-axis guide 63 for guiding the carriage 61 in the y-axis direction; ay-axis ball screw 65 placed under the y-axis guide 63 in the y-axisdirection; a y-axis motor 64 for rotating the y-axis ball screw 65 inthe forward/backward direction; and a carriage screwing part 62 locatedunder the carriage 61 and having a female screw part for moving thecarriage 61 by screwing the y-axis ball screw 65.

The work mechanism part 53 is located under the head mechanism part 52and arranged in the x-axis direction in almost the same constitution asthe head mechanism part 52. The work mechanism part 53 comprises: aworkpiece 70; a mounting table 71 with the workpiece 70 thereon; anx-axis guide 73 for guiding the mounting table 71; an x-axis ball screw75 placed under the x-axis guide 73; an x-axis motor 74 for rotating thex-axis ball screw 75 in the forward/backward direction; and a mountingtable screwing part 72 located under the mounting table 71 and movingthe mounting table 71 by screwing the x-axis ball screw 75.

Note that each of the head mechanism part 52 and the work mechanism part53 has a position detecting means for detecting the position to whichthe head part 60 and the mounting table 71 have moved, which is notshown in the Figure. In the carriage 61 and the mounting table 71, amechanism for adjusting the rotating direction (so-called Θ axis) isincorporated and capable of adjusting the rotating direction by settingthe center of the head part 60 as a center of rotation and of adjustingthe rotating direction of the mounting table 71.

With these constitutions, the head part 60 and the workpiece 70 canreciprocate in the y-axis and x-axis directions, respectively. First,the movement of the head 60 will be described. The y-axis ball screw 65rotates in the forward/backward direction with the rotation of they-axis motor 64 in the forward/backward direction, and the carriage 61integrated with the carriage screwing part 62 moves to any position withthe movement of the carriage screwing part 62 screwing the y-axis ballscrew 65 along the y-axis guide 63. In other words, the head part 60 onthe carriage 61 freely moves in the y-axis direction with the drive ofthe y-axis motor 64. Similarly, the workpiece 70 on the mounting table71 freely moves in the x-axis direction.

As described above, the head part 60 moves to the ejecting position inthe y-axis direction, stops and ejects the droplets 40 insynchronization with the movement of the workpiece 70 located thereunderin the x-axis direction. By controlling relatively the workpiece 70moving in the x-axis direction and the head part 60 moving in the y-axisdirection, a specific drawing and the like can be performed on theworkpiece 70.

The liquid material supply part 54 for supplying the liquid material 93to the head part 60 comprises: a tube 91 a for forming a flow channelcommunicating with the head part 60; a pump 92 for feeding the liquidmaterial 93 into the tube 91 a; a tube 91 b for supplying the liquidmaterial 93 to the pump 92; and a tank 90 communicating with the tube 91b and storing the liquid material 93. The liquid material supply part 54is arranged on one end of the surface table 57.

Considering refilling and changing the liquid material 93, it isdesirable for the tank 90 to be placed on the upper side or underside ofthe surface table 57. However, if the tank 90 can be placed on the upperside of the head part 60, the tank 90 and the head 60 can be connectedby one flexible tube without using the pump 92, so that the liquidmaterial 93 can be naturally supplied by gravity.

The head part 60 holds a plurality of the ejecting heads 68 having thesame structure each other, as shown in FIG. 4. Here, FIG. 4 illustratesthe head part 60 in Embodiment 1 described by referring to FIG. 1, andin FIG. 4, the head part 60 is observed from the mounting table 71 side.In the head part 60, an array constituted by six ejecting heads 68 isarranged so that the longitudinal direction of each of the ejectingheads 68 runs in parallel to the y-axis direction. Twelve ejecting heads68 are arranged in this case. Each of the ejecting heads 68 for ejectingthe liquid material 93 has two nozzle arrays 78 and 79 extending in thelongitudinal direction of each of the ejecting heads 68. One nozzlearray is constituted by 180 nozzles 77 in an array at even intervals.Each of the nozzles 77 of the nozzle array 78 is arranged midway betweentwo nozzles 77 of the nozzle array 79. Adjacent nozzles 77 are arrangedat pitch P at even intervals. Twelve ejecting heads 68 are arrangedstepwise in the x-axis direction so that the nozzles 77 of each of theejecting heads 68 are sequentially arranged at pitch P in the y-axisdirection.

As shown in FIG. 5( a) and FIG. 5( b), each of the ejecting heads 68 hasa diaphragm 83 and a nozzle plate 84. Between the diaphragm 83 and thenozzle plate 84, a reservoir 85 is located in which the liquid material93 supplied through a hole 87 from the tank 90 is always filled. Also,between the diaphragm 83 and the nozzle plate 84, a plurality of walls81 are located. A cavity 80 is a part surrounded by the diaphragm 83,the nozzle plate 84 and a pair of walls 81. Since the cavity 80 isprovided corresponding to the nozzles 77, the number of the cavity 80 isthe same as that of the nozzles 77. In the cavity 80, the liquidmaterial 93 is supplied from the reservoir 85 through a supply port 86located between a pair of the walls 81.

On the diaphragm 83, a resonator 82 is located corresponding to eachcavity 80. The resonator 82 is constituted by a piezoelectric element 82c and a pair of electrodes 82 a and 82 b sandwiching the piezoelectricelement 82 c. By supplying a drive voltage to the pair of electrodes 82a and 82 b, the liquid material 93 is ejected as the droplets 40 fromthe corresponding nozzles 77. In the case of the color filter 110, thedroplets 40 are ejected to the pixel areas 105 surrounded by the filtersubstrate 111 and the boundary layer 112, to form R, G, B pixel areas105R, 105G and 105B.

Next, a description will be given about the controller 55 forcontrolling the constitution as described above with reference to FIG.6. The controller 55 has a command part 30 and a drive part 95. Thecommand part 30 is constituted by CPU 99, ROM, RAM and an I/O interface94. In the command part 30, the CPU 99 processes various signalsinputted through the I/O interface 94 on the basis of the data of ROMand RAM, a control signal is output to the drive part 95 through the I/Ointerface 94 and control is performed.

The drive part 95 is constituted by a head driver 96, a motor driver 97and a pump driver 98. The motor driver 97 rotates the x-axis motor 74and the y-axis motor 64 in forward/backward direction by the controlsignal from the command part 30 and controls the movement of theworkpiece 70 and the head part 60. The head driver 96 controls theejection of the liquid material from the ejecting head 68 and enables aspecific drawing to be performed on the workpiece 70 in synchronizationwith the control of the motor driver 97. The pump driver 98 controls thepump 92 in accordance with the ejection state of the liquid material 93and controls the supply of the liquid material 93 to the ejecting head68 optimally.

The controller 55 is constituted to give signals independent on eachother to each of a plurality of resonators 82. Therefore, the volume ofthe droplets 40 ejected from the nozzles 77 is controlled in each of thenozzles 77 in accordance with the signal from the head driver 96.Further, the volume of the droplets 40 ejected from each of the nozzles77 is variable in the range of 0 pl to 42 pl, which advantageouslypermits a wide range of choice in selecting the volume of the droplets40 and the outer peripheral diameter of the shot drops.

Next, a description will be given about various kinds of high-qualitydisplay apparatus manufactured by using the drawing method and thedrawing apparatus 50 in the invention heretofore explained. Here, acolor filter display apparatus, an electroluminescence display apparatusand a plasma display apparatus will be described as the displayapparatus.

FIG. 7 is a sectional view showing the constitution of the color filterdisplay apparatus. As shown in FIG. 7, a color filter display apparatus100 has polarizing plates 122 and 127 which are arranged opposing toeach other, a color filter 110 at the inner surface of the polarizingplate 122, and a pixel electrode 115 at the inner side of the colorfilter 110. The light from the back light enters from the outer surfacedirection of the polarizing plate 122. A counter substrate 126 is formedat the inner surface of the polarizing plate 127. Between the pixelelectrode 115 and the counter substrate 126, alignment films 121 and 124are formed. At the inner surface of the counter substrate 126, a TFT(thin-film transistor) element (not shown) and a counter electrode 123are formed in a matrix. By enclosing a liquid crystal 125 in the spacesurrounded by sealing parts 128 located between the alignment films 121and 124, the color filter display apparatus 100 is constituted.

By applying the drawing method and the drawing apparatus 50 in theinvention, the color filter 110 can be efficiently manufactured. In thiscase, as shown in FIG. 8( a), the color filter 110 corresponding to theworkpiece 70 in the drawing apparatus 50 in FIG. 3 has the pixel areas105 arranged in a matrix, the border of which is separated by theboundary layer 112 formed by using a dispenser, screen printing orphotolithography. One of color filter materials; red (R), green (G),blue (B) is introduced into each of the pixel areas 105.

As shown in FIGS. 7 and 8, the color filter 110 has the lighttranslucent filter substrate 111 and the light shielding boundary layer112, and pixel areas 105 are formed in the part where the boundary layer112 is not formed. On the upper part of the boundary layer 112 and thepixel areas 105, the overcoat layer 114 is formed. Note that the pixelareas 105 may have striped and deltoid arrangements as well as amosaic-like arrangement as shown in FIG. 8( a).

The pixel areas 105 is formed by using the drawing apparatus 50 and thedrawing method described with reference to FIGS. 1 and 2, and byselectively ejecting the droplets 40 of R, G, B color filter materialsfrom the nozzles 77 shown in FIG. 5 to each of the pixel areas 105formed by being separated by the boundary layer 112 as shown in FIG. 8(b). The pixel areas 105 of each color are obtained by drying the coateddroplets 40. In addition, the overcoat layer 114 can be formed by usingthe drawing apparatus 50 and ejecting an overcoat material from theejecting head 68.

A manufacturing apparatus 130 shown in FIG. 7( b) is a group ofapparatus including an ejecting apparatus for ejecting the droplets 40of the corresponding color filter material to each of the pixel areas105 formed in the color filter 110 of the color filter display apparatus100. Each ejecting apparatus is the drawing apparatus 50. Themanufacturing apparatus comprises: an ejecting apparatus 140R forcoating the red color filter material on all of the pixel areas 105R onwhich the red color filter material should be coated; a drying apparatus150R for drying the color filter material on the pixel areas 105R; anejecting apparatus 140G for coating the green color filter material onall of the pixel areas 105G on which the green color filter materialshould be coated; a drying apparatus 150G for drying the color filtermaterial on the pixel areas 105G; an ejecting apparatus 140B for coatingthe blue color filter material on all of the pixel areas 105B on whichthe blue color filter material should be coated; a drying apparatus 150Bfor drying the color filter material on the pixel areas 105B; an oven160 for reheating (post-baking) the color filter materials of eachcolor; an ejecting apparatus 140C for providing the overcoat layer 114on the layer of the post-baked color filter material; a drying apparatus150C for drying the overcoat layer 114; and a curing apparatus 165 forreheating and curing the dried overcoat layer 114. Further, themanufacturing apparatus 130 has a carrier apparatus 170 for carrying thecolor filter 110 through the ejecting apparatus 140R, the dryingapparatus 150R, the ejecting apparatus 140G, the drying apparatus 150G,the ejecting apparatus 140B, the drying apparatus 150B, the ejectingapparatus 140C, the drying apparatus 150C and the curing apparatus 165,in this order.

Next, the step of enclosing the liquid crystal 125 will be describedwith reference to FIG. 7( a). A first substrate 180 comprises: thepolarizing plate 122 which has already been described; the color filter110; the pixel electrode 115; and the alignment film 121. A secondsubstrate 190 comprises: the polarizing plate 127; the counter substrate126; the counter electrode 123; and the alignment film 124. First, onthe surface of the first substrate 180, the rectangular sealing parts128 to form an area for coating the liquid crystal 125 are formed byusing a dispenser or screen printing. The liquid crystal 125 is ejectedfrom the nozzles 77 of the ejecting head 68 to the inner side of thesesealing parts 128 by using the drawing apparatus 50, similarly to thecase of ejecting the color filter material. After the inner side of thesealing parts 128 has been filled with the liquid crystal 125, thesecond substrate 190 is glued on the sealing parts 128 on the firstsubstrate 180, and the color filter display apparatus 100 is completed.

Further, a description will be given about the electroluminescencedisplay apparatus manufactured by using the drawing method and thedrawing apparatus 50 in the invention with reference to FIG. 9. In anelectroluminescence display apparatus 200, a circuit element part 202 islaminated on a glass substrate 201 and an electroluminescence displayelement 204 constituting the main part is laminated on the circuitelement part 202. A substrate 205 for sealing is formed on the upperside of the electroluminescence display element 204 with a space ofinert gas therebetween.

In the electroluminescence display element 204, a boundary layer 212 isformed by laminating an organic boundary layer 212 b on an inorganicboundary layer 212 a. An emitting part 220 corresponding to the pixelareas 105 of the color filter material in FIG. 8( a) is formed in amatrix by forming the boundary layer 212. In each emitting part 220, apixel electrode 211, a hole injection/transport layer 213 and anemitting layer 210 of red (R), green (G) or blue (B) are laminated inthis order from the bottom, and a counter electrode 203 which is formedby laminating thin films of such as Ca and Al in a plurality of layersby using vacuum evaporation method coats all of the emitting part 220.

The emitting layer 210 is formed by using the drawing apparatus 50 andthe drawing method described with reference to FIGS. 1 and 2, and byselectively ejecting luminescence materials of R, G, B colors from thenozzles 77 of the ejecting head 68 to each emitting part 220 formed bybeing separated by the boundary layer 212, as in the coating of colorfilter material described with reference to FIG. 7. Emitting layers210R, 210G and 210B of each color are obtained in each emitting part 220by drying the coated luminescence materials.

A manufacturing apparatus 230 shown in FIG. 9( b) is a group ofapparatus including an apparatus for ejecting the correspondingluminescence material to each emitting part 220 arranged in a matrix.The manufacturing apparatus 230 comprises: an ejecting apparatus 260 forcoating a functional liquid to form the hole injection/transport layer212 on the pixel electrode 211; an ejecting apparatus 240R for coatingthe red luminescence material on all of the emitting layer 210R on whichthe red luminescence material should be coated; a drying apparatus 250Rfor drying the coated red luminescence material; an ejecting apparatus240G for coating the green luminescence material on all of the emittinglayer 210G on which the green luminescence material should be coated; adrying apparatus 250G for drying the coated green luminescence material;an ejecting apparatus 240B for coating the blue luminescence material onthe emitting layer 210B on which the blue luminescence material shouldbe coated; and a drying apparatus 250B for drying the coated blueluminescence material. Further, the manufacturing apparatus 230 has acarrier apparatus 270 for carrying the emitting layer 210 through theejecting apparatus 260, the ejecting apparatus 240R, the dryingapparatus 250R, the ejecting apparatus 240G, the drying apparatus 250G,the ejecting apparatus 240B, and the drying apparatus 250B, in thisorder.

On the emitting part 220 and the boundary layer 212 formed in thismanner, a counter electrode 203 is laminated as described above, and aninert gas is enclosed into the space between the counter electrode 203and the substrate 205 for sealing to complete the electroluminescencedisplay apparatus 200.

Next, a description will be given about an example of applying thedrawing apparatus 50 to a manufacturing apparatus for manufacturing arear substrate 315 of a plasma display apparatus 300 with reference toFIG. 10. The rear substrate 315 has a plurality of fluorescent parts 325arranged in a lattice-like pattern. In more detail, the rear substrate315 further comprises: a supporting substrate 301; a plurality ofaddress electrodes 302 formed in a striped pattern on the supportingsubstrate 301; a dielectric glass layer 303 formed to cover the addresselectrode 302; and a boundary layer 305 having a lattice-like shape anddetermining a plurality of fluorescent areas. A plurality of thefluorescent areas are located in a lattice-like pattern. Each of aplurality of arrays constituted by the fluorescent areas corresponds toeach of a plurality of the address electrodes 302. The address electrode302 and the dielectric glass layer 303 are formed by screen printing.

In the emitting parts 325, luminescence layers 320R, 320G and 320B areformed by using the drawing apparatus 50, and by selectively ejectingplasma luminescence materials of R, G, B colors from the nozzles 77 ofthe ejecting head 68 to each of the fluorescent areas which correspondsto the pixel area 105 and which is formed by being separated by theboundary layer 305, as in the coating of color filter material describedwith reference to FIG. 7. The rear substrate 315 is formed by drying thecoated plasma luminescence materials.

A manufacturing apparatus 330 shown in FIG. 10( b) is an apparatus forejecting the corresponding plasma luminescence material to each of thefluorescent parts 325 of the rear substrate 315. The manufacturingapparatus 330 comprises: an ejecting apparatus 340R for coating the redplasma luminescence material on all of a fluorescent layer 320R on whichthe red plasma luminescence material should be coated; a dryingapparatus 350R for drying the coated red plasma luminescence material;an ejecting apparatus 340G for coating the green plasma luminescencematerial on the fluorescent layer 320G; a drying apparatus 350G fordrying the coated green plasma luminescence material; an ejectingapparatus 340B for coating the blue plasma luminescence material on theemitting layer 320B; and a drying apparatus 350B for drying the coatedblue plasma luminescence material. Further, the manufacturing apparatus330 has a carrier apparatus 370 for carrying the rear substrate 315through the ejecting apparatus 340R, the drying apparatus 350R, theejecting apparatus 340G, the drying apparatus 350G, the ejectingapparatus 340B, and the drying apparatus 350B, in this order.

Next, as shown in FIG. 10( b), the plasma display apparatus 300 isobtained by bonding the rear substrate 315 and a front substrate 316.The front substrate 316 comprises: a glass substrate 313; a displayelectrode and a display scanning electrode 312 which are patterned inparallel to each other on the glass substrate 313; a dielectric glasslayer 311 formed to cover the display electrode and the display scanningelectrode 312; and a protective layer 310 formed on the dielectric glasslayer 311. The rear substrate 315 and the front substrate 316 arepositioned so that the address electrode 302 of the rear substrate 315and the display electrode/display scanning electrode 312 of the frontsubstrate 316 can be at right angles to each other. A discharge gas 314is enclosed into the area surrounded by each boundary layer 305 at apredetermined pressure.

According to the drawing method in the invention, as described above,the shot drops 1 spread on all of the pixel areas 105 reliably byforming additional shot drops 1 at the corner parts and the like in thepixel areas 105 on which the shot drops 1 do not spread easily. Therebyall pixel areas 105 become uniform in color tone. Using this drawingmethod for manufacturing a display apparatus, a display apparatus with aclear image display can be obtained.

Using the drawing apparatus 50 in the invention, the shot drops 1 can beformed reliably on the pixel areas 105 with various shapes, and aflexible and efficient process can be preformed according to the pixelareas 105.

As described above, the drawing method and the drawing apparatus 50 ofthe invention can contribute to manufacturing a display apparatus suchas the color filter display apparatus 100, the electroluminescencedisplay apparatus 200 and the plasma display apparatus 300. Ahigh-quality electronics device having these display apparatuses can beprovided such as TV, personal computer, car navigation system, digitalcamera, mobile phone and the like. Further, the invention can be appliednot only to a color filter display apparatus, an electroluminescencedisplay apparatus and a plasma display apparatus, but also to a displayapparatus having an electro-emitter (FED (Field Emission Display)), SED(Surface-Conduction Electron-Emitter Display) and the like.

1. A display apparatus, comprising: a color filter having a pixel areaon a substrate, the color filter being made by a) forming a firstplurality of drops by ejecting droplets from a plurality of nozzles of adrawing apparatus to the pixel area, the first plurality of dropsincluding a plurality of drops formed at corners of the pixel area; b)subsequent to a), forming a second plurality of drops in the pixel area,the second plurality of drops being formed along a middle line in thelongitudinal direction of the pixel area and having a predeterminedspacing between two adjacent drops of the second plurality of drops; c)subsequent to b), forming a third plurality of drops in the pixel area,the third plurality of drops including a plurality of drops formed atthe other corners of the pixel area; and d) subsequent to c), forming afourth plurality of drops in the pixel area along the middle line of thepixel area, the fourth plurality of drops having the predeterminedspacing between two adjacent drops of the fourth plurality of drops,wherein each of the drops contains filter material.
 2. A displayapparatus, comprising: a electroluminescence display element having anemitting part, the electroluminescence display element being made by a)forming a first plurality of drops by ejecting droplets from a pluralityof nozzles of a drawing apparatus to the emitting part, the firstplurality of drops including a plurality of drops formed at corners ofthe emitting part; b) subsequent to a), forming a second plurality ofdrops in the emitting part, the second plurality of drops being formedalong a middle line in the longitudinal direction of the emitting partand having a predetermined spacing between two adjacent drops of thesecond plurality of drops; c) subsequent to b), forming a thirdplurality of drops in the emitting part, the third plurality of dropsincluding a plurality of drops formed at the other corners of theemitting part; and d) subsequent to c), forming a fourth plurality ofdrops in the emitting part along the middle line of the emitting part,the fourth plurality of drops having the predetermined spacing betweentwo adjacent drops of the fourth plurality of drops, wherein each of thedrops contains luminescence material.